Impulse kilovolt-ampere meter



Jan. 14, 1941. L. K. Yl-:RGER

IMPULSE KILOVOLT AMPERE METER Filed Nov. 16, 1939 2 Sheets-Sheet 1 inventor.

Lloyd ifi/S?? 5 His Attorneg Jan. 14, 1941. L, K YERGER 2,228,802

IMPULSE KILovoLT AMPERE METER Filed Nov. 16', 1959 2 Sheets-Sheet 2 Inventor:

L Io5d K. Verger,

I-IIS Attorney.

Patented Jan. 14, 1941 2,228,862 IMPULSE movoLT-AMPERE METER.

Lloyd K. Yemen-Buffalo, N. Y., assignor to General Electric Company, a corporation ol' New York Application November 1s, 1939, serial No. 304,770

7 Claims.

My invention relates to a system and apparatus for obtaining a volt-ampere. measurement in response to impulses received from standard integrating meters, for example, from a watthour meter and from a reactive component meter.

United States Patent 1,256,234 describes a mechanism consisting of a sphere which is driven at one point by a. watthour meter at another-point by a reactive component meter in such a way that lo the resultant rotation of the sphere is proportional to volt-ampere hours, and a volt-ampere register is driven from the sphere by a friction wheel VYwhich rides on the sphere at the`point of maximum rotation. Such device has the disadvantage l5 that it requires so much torque from the driving meters that it interferes with their accuracy.

My invention relates to apparatus having such a vector summation sphere operated in response to impulses received from standard meters. By this arrangement detrimental loading of the integrating meters is avoided. The sphere may be made larger and heavier and the contact driving pressures used can be increased so that considerable rugged registering equipment may be driven therethrough without danger of error due to slipping at the driving surfaces. In adopting this scheme, however, it is necessary to smooth out the impulse driving effect and to arrange the apparatus so that the accuracy of registration is independent of the relative rates and the relative times of occurrences of they two sets of impulses, since these conditions will vary over a wide range. The features of my invention which are believed to be novel and patentable will be pointed out in the claims appended hereto. For a better understanding of my invention, reference is made in the following description to the accompanying drawings in which Fig. l shows a perspective view of impulse responsive volt-ampere registering equipment embodying my invention; Fig. 2 is a vector diagram explanatory of the measurements utilized in my invention; Figs. 3 to 7 inclusive are vector representations of different kinds of impulses showing several examples of how the impulses may vary under different conditions; Fig. 8 is a diagrammatic representation of the sphere and connected parts explanatory of the extent to which the sphere should be rotated per impulse in order to substantially eliminate errors due to staggering of the two different kinds of impulses; and Fig. 9 is a curve showing the accuracy behavior of the apparatus under different power factor con,- ditions.

In Fig. 1, a sphere III is supported at three Cil sharp corner of a driving wheel II, another point being a sharp corner of a driving wheel I2 and the other point being a connection to the rounded edge of driven wheel I3. The driving wheels II and I2 make contact at points on the sphere on 5 radii of the sphere which are at approximately 90 degrees to each other or at points spaced approximately one-fourth of the circumference of the sphere. Wheels I I and I 2 have the same fixed axis of rotation, run in the same direction and 1 largely support the weight of the sphere above them. The center of the sphere isv forward of a vertical plane through the axis of rotation of the driving wheels such that the sphere tends to fall forward into contact with driven Wheel I3, which 1: thus prevents the sphere from falling and this three-point suspension maintains the sphere freely rotatable and in driving connection at all points of contact.

The driven Wheel I3 is mounted for rotation in 2t a framework I4 which framework is freely pivoted for rotation about a shaft I5 on an axis which passes through the center of the sphere midway between the disks I I and I2, and the axis of rotation of wheel I3 is at right angles to the shaft I5. 25 This framework I4 may be rotated about its shaft I5 while one-point of the periphery of wheel I3 is maintained in driving and supporting contact with vthe surface of the sphere. The framework I4 is limited in its rotary movement about shaft I5 30 to an angle of about 90 degrees, 45 degrees each way from a point where wheel I3 is in itsl highest position directly above the shaft I5. Wheel I3 thus always helps to support the sphere and to maintain it in a fixed position bodily but allows 35 the sphere to rotate in such position and drive wheel I3. A s thus arranged, if wheel II be driven at a steady rate proportional to the watts of an alternating current circuit and wheel I2 be driven at a steady rate proportional to the reactive com- 4o ponent of the same circuit, the resultant rotation of the sphere will be proportional to the voltamperes of the circuit. 'Ihe axis of rotation of the sphere, however, changes with changes in the power factor of the circuit and in order that the driven wheel I3 be driven at a rate proportional to volt-amperes, theoretically it must adjust its position about shaft I5 so as to always ride on the fastest rotating circumference of the sphere, or it must keep its axis of rotation parallel with the axis of rotation of the sphere. 'I'he fact that the framework I4 in which wheel I3 is. mounted is rotatable about the axis of shaft I5 through the center of the sphere and the fact that wheel I3 is driven in the direction indicated tends to allow such adjustment of wheel I3 to take place automatically and hence to be driven at a rate proportional to volt-amperes, if such adjustment is correctly maintained. Such is the theory of the mechanical vector resultant mechanism of Patent 1,256,234 here utilized to a remarkable degree of accuracy when it is realized that the wheels I I and I2'are to be advanced in response to impulses ratherthandirectlybymeters.- This pointwill be explained more fully after the complete mechanism has been described.

Wheel I I is rotated intermittently at an average rate proportional to the rate of impulses originating in an impulse device driven by a watthour meter I6. In order that the impulse effect may be smoothed out, wheel II is preferably driven by an -electric motor Il controlled by the impulses'. The impulse control circuit includes a double contactor Il driven by the watthour meter for energlzing motor I1 anda double contactor I9 driven by the motor for deenergizing the motor. These contactors may be alike. They produce'similar contact-making and breaking operations. The contactor Ilisoperatedbyasinglecamwheel 20 drivenbythewatthourmeterandhastwosets 2| and 22 of cam operated contacts which open and close alternately. It is important, however, that in this operation, contacts 2| open before contacts 22 close and vice versa. In `the illustration, contacts 22 have .imt opened and contacts 2| are about to close and will do so when its movable contact drops oif the adjacent step in the cam.

The Ystationary contacts are: connected together wheel II by motor through worm gear 29.

to one side of an alternating current source of supply 23.

The movable contact of 'set 2| is connected to the movable contact 25 of contactar I9. The movable contact of set 22 is connected to movable contact 24 of contactor I3. The common relatively stationary contact member 26 of contactor I3 is connected to one terminal of motor I1 and the other motorterminal is connected by wire 2'I to the other side of source 23. 'Two cams 28 and 28 are provided for operating contacter I 9.'

In the illustration, thecontacts 25 and 26 are clod and the contacts 24 and 26 are open. As 'cam 28 rotates, contactor 25 will drop on of its camstep and open its contact with 26. In the meantime contact 24 has been lifted by its cam to a point where it will engage with contact 26 when the latter is lowered by contacter 25 dropping oil.' of its cam.- The common contact 26 moves up and down slightly to assist in the closing operations.

It is seen that in the illustration motor I'I is deenergized and hence is stationary. It is about to be energized by the closingA of contacts 2|, assuming meter I 6 is to be rotating. When this happens, motor I will start and after rotating cam 28 in the direction indicated, a short distance. will open its circuit between contacts 25 and 26, thus stopping the motor. Contacts 24 and 26 have now closed and as soon as meter operated contact: 22 close, motor I'i will again be energized imtil contact 24 drops off of its cam. Cams 28 and 28' are on the shaft of and are driven with Thus it is seen that wheel I I is rotated in accordance with the number of impulses received and independently of their duration, but the rotary action is considerably smoother than what is ordinarily considered as an impulse response. Sudden starting of drivewheels II and I2 such aswmildbecausedbydirectimpulsesis absent and there is no slipping at the driving surfaces.

Certain precautions are necessary in connection with the impulse antan for its practicable use. The impulses comeinat anyrate fromzerowhen the meter I6 is stopped to a maximum rate when meter I6 is operating at maximum speed. It has been found that the maximum impulse rate should preferably not be greater tlnn about one impulse per second. Themotor l1 mthave certain characteristics. It is notessmtlal that it be a synchronous motor or even a strictly constant speed motor. It is important, however, that it be capable of stopping fairly quickly and consistently when deenergized. It muststart andregister an impulse and' be deenergised again in a time not greater and preferably slightly less than the duration of an impulse whentheimpulsesare cominginata rapid rate, since the motor can be energized through the meter operated contacts only so long as these contacts runnin closed when operating at' the maximum rate. If the motor failed to do this, the motor driven contactar would get out of step with the tramntttlng contactor and impulses would be lost. It is also desirable that the motor operate as m as posible during these maximum rate impulses because this makes for smoother rotary action at the receiver. With the five step cams illustrated in Eg. 1 they should turn not less than 1% revolution per impulse-so that as the motor k deenergized at one contact and the cam stops, the other contact will have closed. A lso these cams must turn less than y'. revolution per impulse because if they turn further than this, the contact which has just opened will close again before the motor stops. After a motor has been deenergiaed it coasts a little before it actually comes to a. stop'and motors in general coast further when warm than when cold, due

primarily to the change in viscosity of the oil used in the bearings. A warm motor may also come up to speed Slightly quicker than a cold motor. The motor-coasting distance of the motor when connected to the load represented must be taken into consideration when selecting the arrangement to be used. It has been found that a motor such as described in Warren Patent No. 1,495,936, May 27, 192i having a terminal shaft speed of one revolution per second is satisfactory for this purpose. This refers to the speed of the shaft on which wom gear 29 is located. A satisfactory arranganent exists when the terminal shaft makes from three-fourths to one complete revolution per impulse including coasting. It is important that the motor be deenergized at one contact 25-26 and the other contact 24-26 be closed in a time leas than one second in the example given. However, the motor maybe again energized .by the next impulse through contacts 24-26' before it actually stops coasting provided that when the impulses are coming in at a slow rate so that the motor will coast to a stop between impulses, it never rotates a total distance sumcient to reclose the contact which has just opened. This motor thus turns wheeleII intermittently at an average rate proportional to watthours and also drives a watthour register '30.

At 3| is a reactive component-hour meter and it controls a motor 22 which drives wheel I2 in the direction indicated at an average rate pro- 'portional to that of the reactive component meter 3|. Also it drives a reactive component register 33. 'I'he impulse system between meter 3| and motor 32 is the same as that already described.

Meters I 6 and 3| are of course connected to meter the same alternating current circuit and the impulse transmission ratios between the meters and their registering devices are the same.

' for convenience.

Now that I have arranged for driving the sphere III with power motors rather than by meters, the sphere and the parts driven thereby may be made sufficiently heavy and rugged that considerabie metering equipment may be driven therefrom without meter errors and without slipping. In order that the rotation of wheel I3 may be utilized for such purpose regardless of the rotary position of the supporting framework I4, it is geared to a gear 34 which has a bearing on shaft I5 and hence on the axis of rotation of framework |4. The axis of rotation of gear 34 does not shift when framework I4 shifts and hence gear 34 can be used to drive a metering shaft either directly or through conventional gearing. The driving connection between wheel I3 and gear 34 is through a gear 35 which may be integral with wheel I3 and a gear 36 meshing with gear 35 at right angles thereto. The axis of rotation of gear 36 shifts with the framework about shaft I5 'as a center and hence is always in mesh with gear 34.

Gear 34 drives a shaft 31 through a gear 38. Shaft 31 drives a contact device represented at 39 in order that impulses corresponding to voltampere hours may be transmitted to one or more distant meter receivers for indicating, integrating or recording volt-ampere hours or volt-ampere demand. Shaft 31 also drives a volt-ampere register 40 and a volt-ampere demand meter 4| of any suitable type. In the arrangement illustrated by way of example shaft 31 drives a shaft 42 through gears 43. Register 40 is driven from shaft 42. On shaft 42 is splined a sleeve 43' which rotates with shaft 42 but is Vslidable along the shaft. The sleeve 43' is normally in the position shown where a gear 44 thereon meshes with a gear 45 leading to the demand indicating mechanism. At predetermined time intervals sleeve 43 is raised to momentarily demesh gears 44 and 45 by a lever 46 actuated by a cam 41, which cam is driven at constant speed by a clock motor indicated at 48. 'Ihe gear 44 is returned to the inmesh position automatically as soon as permitted by the cam arrangement. When in mesh and when being driven from the volt-ampere meter, gears 44 and 45 windup a spring 49 and also rotate a pusher member or dog 50. Dog is on a shaft 5| geared to the spring winding shaft 52 through the gears shown at 53. When gears 44 and 45 are demeshed, spring 49 unwinds and returns the dog 5U against a zero stop shown at 54. When the gears 44 and 45 are in mesh, the dog 5U moves a friction pointer 55 up-scale and in a counter-clockwise direction. as shown here. Pointer 55 indicates on a scale 56. It remains in the position to which advanced when the dog returns to a zero position and hence the pointer indicates maximum volt-ampere demand. It will be understood that the apparatus which is driven by shaft 31 may be any suitable type of metering equipment and the devices here represented, as being thus driven, are illustrated by Way of example. y

At 56' is a scale graduated in power factor units, and a pointer 51 fastened to framework I4 indicates on such scale. If the rotary positiongof the framework is accurately maintained in a position corresponding to the true resultant ro tation of the average watt and reactivewatthour components, pointer 51 will indicate the power factor of the circuit metered by the meters I6 and 3|. However, as will be presently explained,

'lower power factors the reverse will be true.

.current lags behind the voltage by an angle X and hence the circuit under these conditions has a lagging power factor less than vunity corresponding to the cosine of the angle of lag, thus the power factor=cos X. This is the usual condition of alternating current circuits intended to be metered by the apparatus described, al-

though it will be appreciated that the angle X may vary considerably and that the meters I6 and 3| may be polyphase meters and measure polyphase watthours and polyphase reactive component hours. The watliour meter I6 measures the in-phase or watt component or, referring to Fig. 2, the product of EI cos X or OW OE. The reactive component meter'measures the reactive component or EI sin X or OR X OE.

At unity power factor the reactive component meter 3| would not run at all and if the current vector shifted to position OI', corresponding to a leading power factor, the reactive component meter would reverse its direction of rotation. The equipment described is not adapted or intended to measure volt-ampere hours 'for both lagging and leading power factors. A leading power factor load is rare and hence it is generally beneficial because it helps to improve thegpower factor of the system from which .other lagging power factor loads are supplied. The equipment described is to be used primarily for measuring lagging volt-ampere hour maximum demand, since it is this factor that power companies desire to determine in order to arrive at proper promotional rates. The apparatus described when arranged for that purpose does not have its lagging volt-ampere measurement' changed or reduced in case the .reactive volt-ampere meter should reverse, due to a leading power factor and this is an advantage. Should the 'system record a leading power factor the customer would be penalized unfairly. It will be noted that the impulse system between meter 3| and the receiver would simply cease to function if meter 3| ran or attempted to run backwards. Neither the contact cam driven by or in response` to meter 3| nor the driving shaft 51 for wheel I2 can rotate backwards because the contact devices, as arranged, prevent this. Also, motor 32v runs only in the proper direction of rotation. Hence the apparatus described responds only to lagging voltamperes. It could of course be arranged to respond only to leading volt-amperes by either reversing the direction of rotation of meter 3| or reversing its impulse transmitting cam wheel.

It will be evident that when the apparatus is in operation for measuring lagging rvolt-ampere hours, the two sets of impulses may come in simultaneously or alternately or in overlapping relation at a power factor where the impulse rates of both meters are equal. p At higher power factors the watthour impulses will come in lfaster than the reactive component impulses, While at It is thus seen that there is no way of predicting just how the two sets of impulses will come in, either as regards their relative rates or as regards the manner in which they may be staggered. It is therefore desirable to arrange matters so that only if some such condition as is represented in the apparatus will register volt-ampere hours, as far as possible. independently d' these factors. A staggered relation of the rotaonal impulses shifts the axis of rotailon'of sphere I3 back and forth independently of power factor changes. I have found that the apparatus can be made to operate with a far greater accuracy and consistency under various power factor conditions than would seem to be possible and without pretending to fully understand just why this is so, I oil'er what I believe to be the explanation and point out certain relations which I inve folmd will give satisfactory results.

In Fig. 3 let the horizontal arrows represent watt-hour component impulses and the vertical arrows reactive component impulses as converted into rotational complments of equal time and distance by the motors 3l and 33. As here represented, the impulses are coming in at the same rate and simultaneously. Th corresponds to a power factor angle of 45 degrees and equal rates of operation of the two impuhe-sending meters. Under these conditions the sphere Il and the wheel I3 which it drives will obviously perform in accordance with the theory of Patent 1,256,234. The wheel I3 will ride on the fastest rotating point of the sphere and rotate a distance directly proportional to volt-amperes, which we may represent vby the resultant vector'OA. In Fig. 4 I have represented the same impulse rate and power factor but the impubes are staggered instead of coming in simultaneously. Under these conditions, if wheel I3 is always t0 ride on the fastest'rotating point of the sphere, it will turn its framework about shaft I I,` degrees between the impulses and in effect follow the stair step line formed by the impulse arrows. If it does this it will rotate a distance considerably greater than the vector 'sum of the impulse vectors and produce an exce error of about 40%. Figs. 5 and 6 represent typical immlsefor a higher power factor condition than is represented in Fig. 6. It is evident that in both cases there would be a serious over-registration error if wheel I3 always rode on the fastt rotating point of the sphere, the assumed err' being slightly less in Fig. 6 where there is only a partial staggering of the watthour and reactive component hour impulses. u

Fig. 'l represents a low powefactor impulse condition where the mst two impulses from the different meters come in simultaneously followed by two from the reactive cnponent meter. Here the assumed error in registration would be slightly less than -in Fig. 6.

According to the way my apparatus is arranged, the assumed errors explained above do not exist except to a very minor degree. VIln my apparatus the wheel I3 rarely rides on the fastest rotating point of the sphere and would) so continuously Fig. 3 is maintained over a number of impulses, in which case the wheel I3 can ride on the fastest rotating point of the sphere.`

As shown in Fig. 1, where five-point impulsereceiving staggered cams are used, the wheels II and I2 which drive the sphere rotate, on the average, 116 revolution per impulse. In other words, an incoming impulse drives sphere I3, even at its fastest rotating point, a distance much less than the distance which wheel I3Y would have to travel about the sphere, (swinging about shaft Il) in order to maintain contact with the fastest rotating point on the sphere under the assumed conditions represented in Figs. 4, 5, 6 and 7. Wheel I3 cannot do this. In the first place when it starts to swing, it is in contact with a point of the sphere which rotates at less speed than the highest peripheral speed point. If this were not so. the wheel I3 would not swing. In the second place this swinging movement of the wheel I3 towards the high speed point of the sphere is in a direction more or les crosswise to the direction in which the sphere-is rotating at the point of contact. 'I'he result is that wheel I3 when out of the theoretically correct position, does not rotate even as fast as the sphere at the point of contact. Its movement is partially rotation on the sphere and partially a sidewise movement across the sphere and the greater the displacement from the theoretically correct position, the greater will be the sidewise movement and less the rotational movement, both because it is on a. slow-moving point of the sphere and because it is cocked at a greater angle to the direction of rotation of the sphere at the point of contact.

If a rotational impulse were much longer than the example given, for example if a rotational impulse rotated the sphere two or three complete revolutions instead of a small fraction of a revolution, then the wheel I3 would have time to shift its position during the early part of such an impulse and would then tend to follow the stair step impulse line of Fig. 4 much more closely than is possible when the rotational impulses are short as contemplated. I prefer to so proportion the rotational length of the impulses to the size of the sphere that it will require not less than ve impulses and preferably more of one kind to shift the wheel from one extreme position to the other. For'example, in Fig. 8, assume the Wheel I3 is in the position shown. that wheel I2 receives no impulses and is stationary and that impulses are coming in and rotating wheel II. Such impulses may be represented in magnitude and direction by the ve large arrows drawn across the diameter of the sphere in the direction in which they cause the sphereto rotate. five such impulses to swing wheel I3 from the position shown through an angle of 90 degrees to a position in line with the fastest rotating part of the sphere. If this is done, the device has a plus registration error of not more than 2% under al conditions which are likely to be encountered Y in practice. Let the angles numbered V1 to 5, inclusive, represent the extent to which the wheel I3 is turned for the respective impulses. Also let the small arrow Ia represent the direction and extent of movement of the sphere at the point of contact with wheel I3 for the first impulse. Arc C then represents the path of contact between wheel I3 and sphere I2. It is seen that the first impulse produces a motion (la) ofthe sphere at its point of contact with wheel I3 which is somewhat less than the motion of the fastest moving point on thesphererepresentedbythelengthofalarge arrow, and much less than the distance the wheel I3hsstoshiftacrothespheretogetinline with the motion of the sphere.` Also, this movement is at first sideways ofV wheel I3. Hence it causes little rotational movement of wheel I3 but largely a sidewise movement about an axis through the center of the sphere. For the second impulse. the wheel I3 is on a point of the sphere which moves somewhat faster, as represented by the arrow 3a, and the wheel has been turned through the angle l so thatit receives more of a rotational component and less of a sidewise component. However, the wheel I3 does notreachthe fastestmovingpartofthe sphere It should require at least or receive the impulse eiiect as a full rotational component until the end of the fth impulse.

It is thus seen why the assumed theoretical errors explained in connection with Figs. 4 to 7, 5 inclusive, are practically eliminated. 'Ihe relations represented in Fig. 8 are illustrative and are not intended to represent exact conditions. Now it is apparent that if we had impulses coming-in in the manner represented in Fig. 4 and 10 sphere I3 rotated such a distance for each impulse, as is represented for the total live impulses of Fig. 8, for example, the wheel I3 would swing through an angle of 90 degrees for each impulse and would then tend to follow the stair step line l5 of Fig. 4 much more closely than it actually does, where the rotation of the sphere per impulse is made small. According to my invention the wheel I3 can be considered as following a path somewhat as represented by the dotted line R, when the conditions are such as represented in Fig. 4. This line is not straight and hence it is apparently longer than the line 0A, Fig. 3, as actually drawn. However, it should also be re` membered that the contact point of wheel I3 with sphere I0 is a point at which the sphere generally rotates slower and never faster than the point of maximum peripheral speed, whereas the length of the impulses represented in Fig. 4 represents the travel of the maximum peripheral 30 speed of the sphere. Hence, if line R could be drawn to the same distance scale as the impulses,

it would be shorter than represented.

I have demonstrated the accuracy of apparatus built in accordance with my invention and obtained an accuracy curve represented in Fig. 9. In this curve the ordinates represent per cent accuracy and the abscissa.4 represents variation in power factor. The average accuracy 'curve A was obtained by varying the power factor of the cir- 40 cuit metered by meters I6 and 3| and measuring the speed of volt-ampere hour shaft 3l. At 0 and unity power factors the apparatus is accurate. Between these power factors there is an average plus error which is quite consistent and averages 11A% between about .2 and .8 power factor. The impulse sequence was varied through various conditions including those represented in Figs. 4, 5, 6 and 7. The maximum error noted was 1.8%. The apparatus used a solid hardened aluminum sphere one inch in diameter. The drive wheels II and I2 andthe driven wheel I3 were inches in diameter. Six-point staggered cams were used in place of the five-point cams shown in Fig. 1 at 28 and 28' and hence the wheels I I and I 2 rotated an average of M2 revolution per impulse and the sphere 1,50 revolution per impulse. From my, investigation I believe that the sphere should not be rotated in excem of about 'I1/2% of its circumference per impulse. 30 On the average power circuit, where such apparatus will be used, the power factor does not as a rule vary suddenly by a. large amount. Also, it will generally vary between certain rather fixed For a circuit, the power factor of which o5 varies between .8 and .2, I may reduce the diameters of the wheels II and I2, or else increase the diameter of wheel I3 from the theoretically correct relation of equal diameters by an amount sumcient to eliminate the substantially constant 70 error of 11/2% represented inA Fig. 9, so that, as-

suming the device has a constant plus error of 11/2%, the volt-ampere hourshaft 31 will rotate at true volt-ampere hour speed. In other words, I may compensate for this substantially constant 75 error by introducing the necessary change in the drive ratio. For a meter for use on a circuit having a variation from unity to .8 power factor the compensation to be introduced would be smaller, for example about 1%. As thus arranged, the error rarely reaches 1/2 of 1 per cent. 5 In discussing the error compensation above, it

' was assumed that the two driving disks I I and I2 made driving contact with the sphere In at exactly the correct theoretical positions, that is, spaced 90 degrees of the circumference. Tests 10 indicate that I may advantageously move the driving wheels Il and I2 very slightly'nearer together than the theoretically correct spacing with a noticeable reduction in the inherent error of the apparatus.` This expedient raises the ends 15 of the average accuracy curve shown in Fig. 9 and lowers the central portion so that the curve has less variation between unity and zero power factor. Using a one inch diameter sphere, I have found that moving the wheels II and I2 each 20 .004 inch closer to the center of the sphere gave an average negative error of about 0.1% over a power factor range of unity to zero.

Another point that should be mentioned is that the framework I4 should be properly balanced 25 about its axis of rotation and for this purpose I represented the adjustable weight 58.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. Measuring apparatus for alternating current 30 power systems comprising meters for measuring the watt and reactive component hours of such a system, impulse transmitters for transmitting current impulses at rates proportional respectively to the watt and reactive component hour 35 measurements of said meters, impulse receivers electrically connected to said transmitters, said receivers comprising a. pair of motor operated contact devices for similarly converting the received impulses into rotational movements'of a 40 deiinite value per impulse, a. pair of spaced disks driven by said receivers in the same direction. a sphere partially supported and driven by said disks at points on said sphere spaced approximately one-fourth of its circumference, and a third disk riding on and driven by said sphere and assisting in the support of said sphere and mounted so that it tends to move about the sphere in line with the fastest rotating part of the sphere for integrating the resulting rotation of said 50 sphere in terms of volt-ampere hours.

2. Measuring apparatus for alternating current power systems comprising meters for measuring the watt and wattlessl component hours of such a. system, current impulse transmitters 55 driven by said meters for transmitting impulses at rates respectively proportional to the measurements of said meters, impulse receivers electrically vconnected to said transmitters comprising electric motors energized by said impulses and in- 50 cluding contact devices operated by said motors in their energizing circuits for stopping such motors after conversion of the received impulses into predetermined rotational movements, a pair of spaced disks driven by said receivers in accordance with their rotational movements -so as to rotate at average rates proportional to the watt and wattless component hour measurements, said disks being driven in the same direction, means for preventing reverse rotation of said disks in case the controlling meter reverses its direction of operation, a sphere partially supported and driven by said disks at points on the sphere spaced apart approximately one-fourth of its circumference, and a third dskriding on said sphere and partially supporting and'driven by said sphere and mounted so that it tends to swing over the sphere in line with the fastest moving part thereof for integrating the resultant rotational movement of said sphere in terms of voltampere hours.

3. Apparatus for combining impulses whichy occur at a rate proportional to the watthours and impulses which occur at a rate proportional to the wattless component hours of an alternating current power circuit into volt-ampere hours comprising a pair of motor driven impulse receivers for converting received impulses into rotational movements such that the summation of the rotational movements of each receiver is proportional to the sum of the impulses received thereby, a pair of spaced driving disks having a common axis of rotation driven in the same direction by said receivers-ln accordance with their rotational movements, a sphere' partially supported and driven by said disks at points on the sphere which are separated by approximately one-fourth of -its circumference, a driven disk riding on said sphere partially supporting the sphere and driven thereby, said driven disk be# ing rotatively mounted in a supporting frame which is rotatable about an axis passing through the center of the sphere midway between said driving disks, whereby said driven disk tends to be driven toward and ride upon the fastest rotating part of the sphere, the dimensions of said parts being such that the sphere is rotated a distance not in excess of about 'l1/2% of its circumference per rotational impulse.

4. Apparatus for combining impulses which occur at a rate proportional to the watthours and impulses which occur at a rate proportional to the wattless component hours of an alternating current power circuit into volt-ampere hours comprising a pair of motor operated impulse receivers for similarly converting each received impulse into rotational movements of predetermined magnitude and direction, a pair of similar disks driven by said receivers, a sphere resting on the peripheral edges of vsaid disks so as to be driven thereby at points on the sphere spaced apart by approximately one-quarter of its circumference, a driven disk riding on the surface of said sphere and driven thereby for the purpose of integrating the vectorial resultant rotational movement of said sphere, said driven disk being supported in a frame that is pivoted on an axis posing through the center of the sphere midway between the driving disks, whereby the driven disk tends to swing in linel with the-fastest rotating part of the sphere, the dimensions and relations of said driving disks and sphere being such that the sphere is rotated not more and preferably less than about '1l/2% of its circumference per rotational impulse and .the driven disk having a slightly greater diameter than the driving disks for the purpose of compensating the vectorial summation principle of said apparatus for errors which may be due to unavoidable staggering ofthe rotational impulse operations of said receivers.

5. Volt-ampere hour measuring apparatus comprising a disk which is intermittently driven at an average rate proportional to the watthours of a power circuit, a similar disk which is intermittently driven at an average rate proportional,

to the wattless component hours -of the same power circuit such that the rotational impulses of said disks may occur in staggered'or overlapping time relation, a l freely rotatable sphere driven by said disks at points on said sphere which are spaced apart approximately onefourth of the sphere's circumference, a third disk riding on and driven by said sphere so arranged that it tends to swing into line with the fastest rotating part of the sphere so as to be driven at a. rate proportional to the vector summation of the individual rotary movements of the driv'- ing disks but departing from a theoretically correct vector summation operation when the rotational impulses occur in staggered or overlapping relation, the rotational movement of said sphere per rotational impulse of the driving disks being a small fraction of a revolution of. such sphere and the size of the driven disk being made slightly larger than the driving disks for the purpose of substantially compensating the vectorial summation operation of the apparatus for errors due, to the staggered and'overlapping occurrence of the rotation impulses.

6. Volt-ampere demand measuring apparatus comprising a maximum demand meter having a demand measuring part which is advanced in proportion to the demand to be measured, power means for advancing said measurement part at a rate proportional to the volt-ampere hours of a power circuit comprising a freely rotatable sphere, a pair of similar disks rotatively supporting said sphere at points spaced apart approximately one-fourth the circumference of the sphere and for driving the sphere, a pair of motors for driving said disks, impulse energizing and control means for one of said motors for causing the same to rotate intermittently, each such rotational operation being proportional to a given value of watthours of an alternating current power circuit, impulse energizing and control means for causing the other motor to rotate intermittently, each such rotational operation being proportional to the same value of reactive component hours .of the same power circuit, a wheel riding on and driven from said sphere, said wheel being mounted in a frame pivoted to swing about an axis through the center of the sphere midway of said driving disks whereby the wheel tends to move into line with and to be driven by the fastest moving part of the sphere but which only approximates such in-line position due to the intermittent manner in which the sphere is driven. a gear wheel mounted for rotation on the axis of rotation of said frame driven from said wheel, and a driving connection between said gear and the aforementioned demand measuring part, whereby said part is positively driven through said wheel, sphere and disks by said motors, the function of said sphere being to vectorially combine theaverage rotational movements imparted thereto by the disks and drive the wheel at a resultant rate proportional to the vector summation of such rotational movements in terms of volt-ampere hours, said parts being adjusted and related to substantially eliminate errors in such vectorial summation operation and which would otherwise be present owing to the intermittent manner in which said sphere is driven.

'1. Apparatus for combining impulses which occur at a rate proportional to the watthours and impulses which occur at a rate proportional to the wattless component hours of an alternating current power circuit into volt-ampere hours comprising a pair of motor driven impulse receivers for 'converting received impulses into rotational movements such that the summation of the rotational movements of each receiver is pro- 'rotational movements, a sphere partially sup- 'ported and driven by said disks at .points on the sphere which are separated by slightly less than one-fourth oi.' its circumference, a driven diskriding on said sphere partially supporting the 10 sphere and driven thereby, said driven disk be- 2,228,802 ,portional to the sum'oi the impulses received ing vrotatively mounted in a supporting frame which is rotatable about an axis passing through lthe center of the sphere midway between said driving disks, whereby said driven disk tends to be driven toward and ride upon the fastest rotating part oi' the sphere, the dimensions of said parts being such that the sphere is vrotated a distance not in excess of about rl1/ of its circumference per rotational impulse.

LLOYD K. YERGER. 

